A window screen consists of mesh, or screening, supported by a lightweight rectangular frame. The frame includes four essentially straight segments, i.e., the top, the bottom, and the left and right sides, which are connected at adjacent ends to form the corners of the frame. The ends of the segments are either cut at forty-five degree angles and connected directly together to form ninety-degree corners, or the ends are cut to mate with "corner keys," which are corner-shaped connectors. Each corner key basically consists of two legs with their adjacent ends joined at a ninety degree angle to form a corner. The free ends of the legs fit within or over the adjacent ends of the frame segments, to connect these segments via the corner, at a ninety-degree angle.
The screen frame slides either vertically or horizontally along tracks on the outer edges of the window jambs. The screen does not fit tightly in the tracks, since the screen will ordinarily require replacing several times before the window requires replacing. Accordingly, the screen must be able to be readily removed from and installed in the tracks.
In prior known window screen assemblies the screen frames include on at least one side a segment stop, in the form of a narrow ridge. This ridge prevents the screen from penetrating too deeply into the track. Each ridge, which is offset from the outer edge of the segment, runs parallel to the edge, and extends the entire length of the segment. It thus essentially widens the segment, so that only the portion of the segment that is to the outside of the ridge rides within the track. The screen can then be shifted and removed, or withdrawn, from the tracks.
The frames must be lightweight and low cost to be competitively marketed. Including these segment-long ridges on the frame segments increases the weight of the segments and the amount of raw material used to make them. To minimize the weight and the materials used, the ridges must be quite narrow. However, manufacturing segments with these narrow ridges requires custom designed, and thus, expensive machinery, which adds to the cost of manufacture.
After the frame segments are manufactured, they are assembled to form the frame. Then, handles used to move the screen along the tracks are attached, either to the side or bottom segments of the frame. This assembly process is labor intensive, which adds to the cost of the frame. Further, holes for screws or other cut-outs for attaching the handles to the frames must be included on the frame segments, which complicates the manufacturing process. Alternatively, the handles may be incorporated into an extruded frame segment, which adds to the cost of producing the segment, and thus, the cost of the frame.
What is needed is a window screen frame that is simpler and less expensive to manufacture than the prior, known frames.